OLYMPIA - With the start of boating season, the departments of Ecology (Ecology) and Fish & Wildlife (WDFW) want to remind boaters that they have an important job to do: cleaning off their boats and gear to protect Washington's waters against non-native invasive species such as Eurasian milfoil and potential invaders such as zebra mussels.

A new law that took effect last year gives the Washington State Patrol and WDFW the ability to detain boats and inspect them to be sure they are not carrying prohibited plants or animals. It is now against the law to transport any aquatic plant on boats, trailers, fishing gear or bait wells.

"These invasive species get into our lakes and streams on propellers, trailers, nets and other fishing gear," said Kathy Hamel, who manages Ecology's aquatic-weeds program. "They choke out native species and destroy fish and wildlife habitat, and can make it impossible to swim or boat in the water. Some species can actually be dangerous for swimmers, especially children."

Noxious weeds such as milfoil are typically spread to lakes on boat trailers and fishing gear. It takes only a tiny fragment of a noxious plant, sometimes less than an inch, to start a whole new infestation.

"Milfoil is very widespread over the whole state. You can see it growing where the traffic patterns are, such as along the I-5 corridor in Western Washington. Every year, we find more infestations," Hamel said.

It isn't just noxious weeds that are a concern. Invasive animal species such as zebra mussels often cling to aquatic plants, even if the plants themselves aren't a problem.

"It's terribly important that people clean their boats and gear every single time, before and after going into water," said Hamel.

"Live zebra mussels have been found in recent years on several boats that were checked at highway weigh stations as they entered the state, so we know this is a pathway for their introduction," said Scott Smith, who heads WDFW's aquatic invasive-species program.

Zebra mussels have taken a toll on the ecosystem and economy in other areas of the country where they have been unwittingly introduced and have proliferated, Smith said. In the Great Lakes area, zebra mussels have altered the entire ecosystem of some waters, taking food sources away from native species and clogging water intake pipes used for irrigation and municipal water supplies.

The state has been monitoring for zebra mussels for three years, and none have yet been found in Washington waters, Smith added. "So far, Washington is free of zebra mussels, and we want to keep it that way."

For help controlling weeds in an infested lake or stream, contact Hamel at 360-407-6562 or your county's noxious-weed board. For help with aquatic invasive species, contact Pam Meacham at the Dept. of Fish and Wildlife, 360-902-2741.